Low noise amplifier (T466E)

Found in 1948 MIT documentation, this 4-tube amplifier is characterized by its low noise level.

Model speed control (CB5375E)
This circuit is from an 80's documentation. The BC108 can be replaced by the BC548 and the 2N3055...
DAC38RFxx 14-bit DACs for 9 GSPS
May 2017 - These new Digital to Analog converters from Texas Instruments, available from Mouser...
Variable Filter (CB4600E)
This circuit prevents the passage of frequencies in a range starting at 1 kHz and can be adjusted...